title: Foreshortening affects both uphill and downhill slope perception at far distances.
abstract: Perceived slope varies with the viewing distance, and is consistent with the effects of foreshortening. Distant viewing makes uphill slopes appear steeper and downhill slopes flatter than does near viewing. These effects are obvious to skiers and climbers in mountainous country. They have also been measured in outdoor experiments with controlled viewing distances. There are many other sources of slope illusions.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Ross
mesh_terms: D000818:Animals; D003071:Cognition / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D013028:Space Perception / Q000502:physiology*; D013037:Spatial Behavior